I would say if it is an unported head, then they should be cleaned and checked.
Usually just a bit of port cleanup and good valve job will improve airflow quite a bit.

The Trick Flow heads are CNC ported and they were good out of the box.
The Koffels ported B1 B/S heads were good out of the box.
The Hughes Engines Ported Max wedge Victors were good out of the box.